Prevalence of Chronic Oedema in Obese Patients

The clinical assessments included in both stages of the study will identify the presence and severity of swelling in each of the affected areas. Each assessment will consist of a clinical examination of the patient's legs and abdomen to look for swelling and changes in the skin associated with this.

Assessments carried out in Stage 1 will include bioimpedance and tissue dielectric constant (TDC) techniques.

• Bioimpedance measures the total fluid within a limb. This test passes an extremely small electrical current through the participant's body and measures the resistance to the flow of this current. The participant will not feel anything when the measurement is carried out as the current is very small, similar to the strength of a watch battery. If the participant is able to, the test will be undertaken with the participant lying down on an examination couch or sitting in a chair. Small stickers will be placed on the participant's hands and feet, and clips attached to these.
• The TDC measures fluid levels at different points. In order to record these fluid levels, a probe will be placed against the participants' skin on their feet, lower legs, and thighs.

Assessments carried out in Stage 2 will include bioimpedance, TDC, and also perometry (or measuring using a tape measure).

• This test measures the size and shape of the participants' legs, and can be undertaken by one of two methods depending on their mobility. If they need to stay in a chair or examination couch during the assessment, the size of their legs will be measured at different points using a tape measure. However, if possible, a device called a perometer will be used. Participants will be asked to stand with one leg in the frame of the perometer while it is moved up and down the leg. The frame contains lights which are used to measure the size and shape of the limb.

None of the assessments included in either stage should cause any pain or discomfort.

The questionnaires, which will be completed in both stages, concern the participants' quality of life and mobility.

• The EQ-5D questionnaire compares quality of life over time well and can assess the health utility of the participants. The EQ-5D scores can be used to calculate quality-adjusted life years.
• The GAD-7 (Generalised Anxiety Disorder 7-item Scale) and PHQ-9 (Patient Health Questionnaire - 9) questionnaires will be used to assess the anxiety/depression of the participants. Stage 1 participants will have completed these before their study assessments so the study team will obtain these results from their clinical records. Stage 2 participants will complete the questionnaires as part of the study assessments.
• The SF-36 questionnaire will assess the mobility of the participants and give general health-related quality of life scores.
• The LYMQOL questionnaire, which will only be given to participants who have oedema, is a validated, condition-specific, quality of life instrument. It can be used both: to assess lymphoedema of the limbs and as an outcome measure.

Inclusion criteria

• Adults who have capacity to give informed consent.
• Ability to understand the assessment questionnaires in English.

Stage 1 - all patients accepted for referral. There are no co-morbidities that would exclude people.

Stage 2 - patients that undergo bariatric surgery.

Exclusion criteria

• Patients under the lower age limit of 18.

Stage 2 - By-Band-Sleeve study participants who are taking part in the randomisation part of the study.